1. Field of the Invention
This invention is in the field of continuous refining of contaminated copper in the molten phase and has to do with controlling the conditions of an oxygen containing gas stream in the form of a jet, and directing the same vertically in the form of a confined energy rich stream at the essentially smooth surface of a copper metal bath to produce a torus-type rotating stream under controlled conditions of pressure, velocity, spacing and jet force.
2. Description of the Prior Art
A continuous method for the refining of contaminated copper in the molten phase is described in the German Pat. No. 2,061,388 and its British counterpart, British Pat. No. 1,348,513 published Mar. 20, 1974. In this type of procedure, the molten copper is conveyed into a treatment chamber through several reaction zones in countercurrent contact with hot gases and is thereby freed of impurities. In the last reaction zone, fuel and an oxygen containing first gas are conveyed in less than stoichiometric proportions, thereby producing a reducing heating gas. In the zones prior to the last reaction zone, an after combustion of fuel which is still unburnt in the heating gas is carried out through an additional supply of a second oxygen containing gas. German Pat. No. 2,061,388 and its British counterpart describe an efficient continuous process for the refining of contaminated copper in the molten phase. The disclosure of the corresponding British Pat. No. 1,348,513 is incorporated herein by reference.
Reference is also made to Wuth U.S. Pat. No. 3,902,895. This patent deals with a method for the separation of elements from a liquid metal bath, particularly copper, wherein reaction gases are blown in the form of a gas jet approximately perpendicular to the bath surface and with sufficient force so that the melt rotates essentially like a torus, resulting in a reaction unit with definite material transition, limited by the convection conditions of the system.
In the system shown in the British patent, the continuity of the process can be achieved and maintained only by means of absolutely constant flow densities of material of the liquid and gaseous reaction participants. However, this constant flow was not attainable in the prior art with the known methods of charging of the gas to the metal bath. For example, the gas might be brought in contact with the metal by means of inclined or vertical blowing jets, or by means of lances located under the bath surface. Under these circumstances, however, there is no capability for reproducing material transfer and the maintenance of a definite reaction system with uniformly measurable exact parameters. The reason for this is that with this type of contact system, the reaction depends on a number of incidental and therefore changeable parameters. For example, such elements as depth of immersion, shape and/or alteration of the lance configuration changes the quantity and velocity of the gases. In addition, accidental gas bubble formation as well as uncontrolled spraying may result.
With the blowing technique described in the Wuth patent alone, however, copper refining could not be carried out continuously. The Wuth patent is directed strictly to the achievement of a definite convection flow through special conditions of blowing.